Key Difference – Space vs Universe
Although the two terms space and universe are often interchanged by many people, there is a distinct difference between space and universe. Space typically refers to the void that exists between celestial objects whereas universe refers to all celestial objects as well as space. Thus, the key difference between space and universe is the inclusion of celestial objects.
CONTENTS
1. Overview and Key Difference
2. What is Space
3. What is Universe
4. Side by Side Comparison – Space vs Universe
5. Summary
What is Space?
Space, also known as outer space, is the void that exists between celestial bodies, including planet Earth. It consists of a hard vacuum comprising a low density of particles, mainly a plasma of hydrogen and helium. It also includes magnetic fields, electromagnetic radiation, neutrinos, dust and cosmic rays.
Intergalactic space takes up most of the volume of the Universe. In most galaxies, 90% of the mass is in an unknown form called dark matter, which interacts with other matter through gravitational forces.
The space near Earth is classified into several astronomical categories or standards. It is generally accepted that space begins at the Kármán line on earth.
Geospace
This is the region of outer space near our planet. This includes the upper region of the atmosphere and the magnetosphere.
Interplanetary Space
This is the space around the planets and the Sun of the solar system. It has a continuous stream of charged particles from the Sun, which is called the solar wind, creating a very thin atmosphere.
Interstellar Space
This is the physical space within a galaxy that is not occupied by planetary systems or stars. It spreads to the edges of the galaxy and fades into the intergalactic void.
Intergalactic Space
This is the space between galaxies. This has cosmic voids between large-scale structures in the universe.
Figure 1: The interface between the Earth’s surface and outer space.
What is Universe?
The universe can be basically defined as everything that exists. It consists of all types of physical matter and energy, solar systems, planets, galaxies, and all contents of the space.
Planet: A celestial body such as Earth or Mars, moving in an elliptical orbit around a star.
Star: A celestial body that generates light and other radiant energy
Solar System: The Sun and all objects, including planets, asteroids, comets, orbiting around it.
Galaxy: A group of many stars, along with dark matter, gas and dust.
Most scientists use the scientific model of Big Bang theory to explain the universe. Big Bang theory puts forth the concept that the Universe expanded from a very hot, dense phase where all the matter and energy of the Universe was concentrated. Most of the universe is thought to be made of an unknown matter known as dark matter.
Figure 02: Universe
What is the difference between Space and Universe?
Space vs Universe |
|
| Space refers to the void that exists between celestial objects. | Universe refers to the entirety of all physical matter and energy, solar systems, planets, galaxies, and all contents of the space. |
| Celestial Objects | |
| Space does not include celestial objects; it includes only the void between them. | Universe includes all celestial objects. |
| Size | |
| Space consist of magnetic fields, electromagnetic radiation, neutrinos, dust and cosmic rays. | Universe consists of planets, stars, galaxies, as well as space. |
Summary – Space vs Universe
The main difference between space and universe is that space refers to the void between celestial objects whereas universe refers to the entirety of all physical matter and energy, solar systems, planets, galaxies, and all contents of the space. Thus, it can be surmised that space is a part of the universe.
Image Courtesy:
1. “Galaxy-2048×1152” By Gamemasterz – Own work (CC BY-SA 4.0) via Commons Wikimedia
2. “Earth’s atmosphere” By Kelvinsong – Own work (CC BY-SA 3.0) via Commons Wikimedia